Pneumatic power booster, especially for brake systems for motor vehicles

摘要

A rear and a front housing section (10 and 20), are both of pot-shaped design, each with a casing (14 and 24) and a collar (16 and 26) and connected to one another to form a cylinder housing (10, 20), inside which a piston plate (30) is axially movable. The cylinder housing (10, 20) contains a diaphragm (40), which has an inner section (42) supported on the piston plate (30), an outer edge (44) clamped between the collars (16, 26) and a U-type bellows (46) arranged between inner section and outer edge and in the cylinder housing (10, 20) separates two chambers (48, 50) from one another. In a rest position the U-type bellows (46), with at least approximately equal pressure in the two chambers, extends forwards from the piston plate (30) inside the rear housing section (10). With a rise in pressure gradient from the rear to the front chamber the piston plate (30) moves forward and the U-type bellows (46) is progressively applied forwards onto the casing (24) of the front housing section (20). The front housing section (20), in an area of its casing (24) lying in front of its collar (26) to which the U-type bellows (46) can be applied, has a larger inside diameter (d24) than on the collar (26) itself. Consequently the U-type bellows (46) is inflated outwards at an early stage of actuation so that the booster acquires a large effective diameter. <IMAGE>